172 INTRODUCTION 



tendency to over-sharpen the distinction between percep- 

 tion and conception by ignoring the idea of development, 

 while the defect of Leibniz is his inclination to define the 

 common quality or function ('perception') by its lowest 

 rather than its highest terms, to interpret it, not as essen- 

 tially self-consciousness, which is its most perfect develop- 

 ment, but as mere representation or multiplicity in unity, 

 to which consciousness and self-consciousness are added 

 characteristics ] . Yet while Kant makes an advance from 

 the position of Leibniz, they are on similar lines, and we 

 can read their reconciliation in Hegel 2 . 



Leibniz does not give any clear account of the relations 

 between the principle of contradiction and that of suffi- 

 cient reason, as he uses them in his philosophy ; but it is 

 evident that he considered them to be, in some way, 

 ultimately in harmony. The tendency of Kant, on the 

 other hand, is to emphasize the distinction between them, 

 while treating each, apart from the other, as abstract. 

 The course of Kant's pre-critical thinking makes this clear. 

 He begins with the Wolffian view that the principle of 

 sufficient reason is reducible to that of contradiction 3 , and 

 accordingly, that the principle of contradiction is the sole 

 ultimate principle of knowledge. But gradually he comes 

 to see that the principle of contradiction has to do with 

 nothing but the form of thought and that it yields merely 

 a self-consistent system of knowledge, based on dogmatic 



1 In this, I think, there is to be found the explanation of the 

 separation (almost amounting to a distinction of kind) between 

 rational souls and the other Monads, which Leibniz makes with 

 such apparent inconsistency. Cf. this Introduction, Part iii.p. 116. 



2 ' The doctrines of Leibniz formed the permanent atmosphere 

 of Kant's mind. His reading of Hume in middle life no doubt 

 helped to determine the mode in which he absorbed and trans- 

 formed them ; but it was upon them, as we find in the Critique no 

 less than in his earlier writings, that his mind constantly worked, 

 and there would be a better case, at any rate, for describing him 

 as a corrected and developed Leibniz than for putting him in such 

 a relation to any one else/ T. H. Green, Works, vol. iii. p. 134. 



3 Cf. Principiorum primorum cognitionis metaphysicae nova dilucidatio 

 ( T 755) (Rosenkranz, i. 4; Hartenstein, iii. 4). 



